The present invention relates to telescopic sights, and more particularly relates to an adjustment mechanism for the zoom of a firearm scope.
Firearm scopes are well known telescopic sight mechanisms which are mounted to the top of a firearm (e.g., rifle, shot gun, hand gun, etc.) to allow the shooter to view distant objects for greater shooting accuracy. Many scopes include the ability to adjust the optical magnification via a rotatable ring which may be rotated by the shooter to set the desired magnification. The rotatable ring is typically located in a position which requires the shooter to take one hand off the firearm so that they may reach and rotate the ring while simultaneously looking through the scope eyepiece for visual feedback while adjusting the magnification. Having to take a hand off the firearm during this process is undesirable in several respects. For example, when hunting with a rifle or shotgun, once the target has been acquired, any movement of the hand off and then back on the rifle or shotgun can also move the firearm off the target and decrease shooting accuracy. Any movement also has the potential of visually and/or audibly altering prey that may then run before the shooter has a chance to fire the shot. The following are some examples of prior art mechanisms for adjusting the zoom of a firearm scope:    U.S. Pat. No. 2,913,826 issued on Nov. 24, 1959 to Petty    U.S. Pat. No. 3,492,733 issued on Feb. 3, 1970 to Leatherwood    U.S. Pat. No. 3,782,822 issued on Jan. 1, 1974 to Spence    U.S. Pat. No. 5,180,875 issued on Jan. 19, 1993 to Berry, Jr. et al    U.S. Pat. No. 5,194,987 issued on Mar. 16, 1993 to Bausch & Lomb Incorporated    U.S. Pat. No. 5,276,554 issued on Jan. 4, 1994 to Nassivera    U.S. Pat. No. 5,521,757 issued on May 28, 1996 to Olson    U.S. Pat. No. Des. 342,537 issued on Dec. 21, 1993 to Olson    U.S. Pat. No. 5,924,211 issued on Jul. 20, 1999 to Wambold, Jr., et al    U.S. Pat. No. 6,226,880 issued on May 8, 2001 to Pitre    U.S. Pat. No. 7,246,461 issued on Jul. 24, 2007 to Wooden    U.S. Pat. No. 7,552,559 issued on Jun. 30, 2009 to Day    U.S. Pat. No. 7,684,114 issued on Mar. 23, 2010 to Thomas
While the above patents illustrate various mechanisms which are used in conjunction with a firearm scope zoom, each have drawbacks including, for example, a complex design which translates into a high cost to manufacture, dependency on right or left hand use, complicated installation and use, and designs which are susceptible to being easily damaged. There therefore remains a need for an improved mechanism for adjusting the zoom of a firearm scope which overcomes the drawbacks of the prior art.